With XU configured as a router with both integrated NIC and Gigabit dongle, making a kernel with distcc causes the XU to shut down completely with no log messages. Sustained test with iperf does not cause the machine to crash.
Tested with master distcc host on 100Mbs side and two slave machines on the Gbit side.
More info on the forums: http://forum.odroid.com/viewtopic.php?f=73&t=5188